Blast machine system and method



y 1963 A. H. FREEMAN ETAL BLAST MACHINE sysmm AND METHOD Filed May 11, 1962 FIGI INVENTORS ARDEE H FREEMAN FREDERQCK J. PICHARD 05m, M, @944 M M ATTORNEYS This invention relates to blast machine systems such as are used to clean up castings or other semi-finished workpiecesj and more particularly to an improved system having ad alternative blast media cycling arrangement whereby contaminant accumulations may be from time to time purged from the system, such as after each heavy sand loading cycle of operation thereof. In consequence the blast machine may be at all times more efiiciently employed to perform on castings or other workpieces, rough cleaning and finish clean-up processes.

Previousiy, because of the greatly variable sand loads incident for-example to core knockout and rough cleaning and f nish-cleaning operations, shot blast machine systems haste been found propense to accumulating at various stations therein concentrations of harmful percentages of sand and debris contents, which accumulations on occasion dislodge and then flood the blast machine with intolerable surges of debris. Such tendency invariably exists for example in the feed hopper located just above blast machine feed inlet.

The present invention contemplates, in a blast machine system, meansfor selectively dumping such accumulations through ia by-pass conduit to an intermediate stor age hopperzend thence to the system separator, thereby by-passing ih blast machine and protecting the latter ar and otherwise inefficient operation. It

that only slight increases of sand percentt shot and sand mixture will cause tremendous wear-of the blast machine centrifugai wheel and liners etc., asiwell as reducing the blasting efiiciency of the machine;

Thus, a primary object of the present invention is to provide in a gflast machine system, means for eiiiciently by-passing contaminant accumulations and recycling them 'gneparator, whereby to reduce the blast ma- Other objects and to the accompanying drawing wherein:

FIG. 1 is apogxewhat schematic elevational view of one form of system of the invention; and

FIG. 2 is a fragmentary sectional view through a feed hopper component of the system, illustrating undesirable accumulationsliilerein.

As shown iggflle drawing, a blast machine system embodying the imtion may comprise generally a tumble blast unit ld ineluding a candle type conveyor 12 of table or the which supports and tumbles a load of processed, such as are indicated A shot throwing machine 16 is disposed above the load of castings and operates pieces, as is wehfienown in the art. With a view to simplification of this specification the tumble blast and abrasive throwing machine components will not be illustrated and described in detail; the details of construction and operation of typical examples thereof being fully disclosed and explained Patents 2,104,055 and 2,819,562. However, it is tof h'e understood that in lieu of the specific forms of workpiece supporting and tumbling and shot throwing devices'f il lustrated herein and disclosed in the referenced patents, any other suitable forms of equipment may be employed, such as for example swing table machines as disclosed in US. patent application S.N.

ted States Patent 14,903, filed March 14, 1960, by Alfred Schnetzer, now Patent No. 3,041,786. The hopper and feed chute for supplying abrasive to the unit 16 are indicated at 18 and 20, respectively, and the conveyor for carrying away spent abrasive and debris is indicated at 22.

debris circulating and separation system such as may include the conveyor 22 shown as discharging the debris an an abrasive mixture from machine 10 to the foot of an elevator 24. Elevator 24 delivers pending U.S. patent application Serial August 4, 1959. refuse discharge spout 30 delivering into any suitable separator delivers into the hopper 18. A control valve as shown at 38 is disposed in the feed line to the abrasive throwing machine 16.

After each batch of castings or the like suitable means into the blast machine the door of the machine is then closed and the castings are tumbled and/or turned while the unit 16 is activated with the valve 38 open so that the blast operation dislodges sand and/or surface scale or other debris from the workpieces. During this process the contaminated abrasive cycles through the separator so that the dislodged sand and scale and is loaded by any Also, this will impose undue Wear upon the blast machine parts.

To avoid the diificulties and disadvantages referred to, we provide a separate bypass conduit or conveyor as indicated at 40 to permit periodic dumping" of the entire contents of the hopper 18. The chute 40 leads to a 24, which in turn leads the chute 40 being controlled by a capacity of the separator; the separator functioning to discard from the system the worn-out blast media and fine debris from the mixture. When hopper 42 is empefficiency; outlined above may be performed either manually or au- 1. A unit machine system for blast-cleaning workpieces, said machine system including a workpiece receiving device adapted to turn the workpiece, a blast machine arranged to bombard the workpiece as it is turned, a feed hopper delivering blast media to said blast machine, a separator receiving contaminated blast media residual to the blasting operation, said separator having a debris discharge and a reusable blast media discharge separate therefrom, said reusable blast media discharge delivering to said feed hopper, a by-pass conveyor returning from said feed hop per to an intermediate storage hopper arranged to discharge to said separator intake, a first valve controlling passage through said by-pass conveyor, a second valve controlling passage from said storage hopper to said separator, a third valve controlling passage to said blast machine, said valves being selectively actuatable so as to either block passage of blast media through said blast machine while causing circulation of all material in the system through said separator, or to cause recycling of the reusable blast media through said feeder hopper and said blast machine against said workpieces.

2. A unit machine system for blast-cleaning workpieces, said machine system including a workpiece receiving device adapted to turn the workpiece, a blast machine arranged to bombard the workpiece as it is turned, a feed hopper delivering blast media to said blast machine, a separator receiving contaminated blast media residual to the blasting operation, said separator having a debris discharge and a reusable blast media discharge separate therefrom, said reusable blast media discharge delivering to said feed hopper, a bypass conveyor returning from said feed hopper to an intermediate storage hopper arranged to discharge to said separator intake, a first valve controlling passage through said bypass conveyor, a second valve controlling passage from said storage hopper to said separator, a third valve controlling passage to said blast machine, said valves being selectively actuatable.

3. A unit machine for cleaning out cores and heavy surface debris from castings and then finish-cleaning the same, said machine comprising, a casting reeciving device adapted to turn the castings, an airless blast device arranged to throw loose blast media at the castings as they are turned, a feeder delivering media to said blast device, a separator receiving debris and spent media falling away from said castings, said separator having a debris discharge and a reusable media discharge separate therefrom, said reusable media discharge delivering to a hopper above said feeder, a bypass conduit interconnecting said hopper and said separator intake, a first valve controlling passage through said bypass conduit, a second valve controlling passage through said feeder, and control means operable to alternatively set said valves so as to block passage of blast media through said feeder while circulating all material falling away from said castings through said separator and alternatively cycling the reusable media therefrom through said feeder and said blast device against said castings.

4. A unit machine for sequentially knocking out hard to dislodge cores form castings and then finish-cleaning the same, said machine comprising, a casting receiving device adapted to tumble the castings, a blast device arranged to throw blast media at the castings as they are tumbled, a feeder delivering blast media to said blast device, a sep arator receiving debris and spent media falling away from said castings, said separator having a debris discharge and a reusable media discharge separate therefrom, said reusable media discharge normally delivering to said feeder, a bypass conveyor returning from said media discharge to said separator intake, a first valve controlling passage through said bypass conveyor, a second valve controlling passage through said feeder, and control means operable to sequentially control said valves so as to initially block passage of media through said feeder while circulating all material falling away from said casting through said separator and subsequently cycling the reusable media therefrom through said feeder and said blast device against said casting.

5. A unit machine for cleaning out cores and heavy surface debris from castings, said machine comprising, a casting receiving device adapted to tumble the castings, an airless blast device arranged to throw loose blast media at the castings as they are tumbled, a feeder delivering media to said blast device, a separator receiving debris and spent media falling away from said castings, said separator having a debris discharge and a reusable media discharge separate therefrom, said reusable media discharge delivering to a hopper above said feeder, a bypass conduit leading away from the bottom of said hopper and a valve controlling passage through said by-pass conduit and operable so as to initially block passage of material through said bypass conduit while circulating all material falling away from said castings through said separator and subsequently cycling the reusable media therefrom through said feeder and said blast device against said castings.

6. A method of cleaning castings and for segregating usable blast media and debris from a system including a blast machine operating on castings and a hopper feeding and said machine with blast media, which method comprises placing a casting requiring to be cleaned on a support arranged to turn said casting for shaking out the foundry core material and other loose debris while conveying said debris to a separator having a debris discharge and a cleaned blast media discharge delivering to said hopper, then shot-blasting said casting while it is being tumbled to remove residual core and surface material and delivering the spent shot and debris materials to said separator while periodically bypassing the accumulations within said hopper back to said separator, whereby accumulations of fine debris in said hopper may be periodically dumped to purge the system thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,104,055 Peik Jan. 4, 1938 2,305,451 Turnbull Dec. 15, 1942 2,424,955 Potter July 29, 1947 2,440,819 Evans May 4, 1948 2,449,745 Jewell Sept. 21, 1948 

1. A UNIT MACHINE SYSTEM FOR BLAST-CLEANING WORKPIECES, SAID MACHINE SYSTEM INCLUDING A WORKPIECE RECEIVING DEVICE ADAPTED TO TURN THE WORKPIECE MACHINE ARRANGED TO BOMBARD THE WORKPIECE AS IT IS TURNED, A FEED HOPPER DELIVERING BLAST MEDIA TO SAID BLAST MACHINE, A SEPARATOR RECEIVING CONTAMINATED BLAST MEDIA RESIDUAL TO THE BLASTING OPERATION, SAID SEPARATOR HAVING A DEBRIS DISCHARGE AND A REUSABLE BLAST MEDIA DISCHARGE SEPARATE THEREFROM, SAID REUSABLE BLAST MEDIA DISCHARGE DELIVERING TO SAID FEED HOPPER, A BY-PASS CONVEYOR RETURNING FROM SAID FEED HOPPER TO AN INTERMEDIATE STORAGE H OPPER ARRANGED TO DISCHARGE TO SAID SEPARATOR INTAKE, A FIRST VALVE CONTROLLING PASSAGE THROUGH SAID BY-PASS CONVEYOR, A SECOND VALVE CONTROLLING PASSAGE FROM SAID STORAGE HOPPER TO SAID SEPARATOR, A THIRD VALVE CONTROLLING PASSAGE TO SAID BLAST MACHINE, SAID VALVES BEING SELECTIVELY ACTUATABLE SO AS TO EITHER BLOCK PASSAGE OF BLAST MEDIA THROUGH SAID BLAST MACHINE WHILE CAUSING CIRCULATION OF ALL MATERIAL IN THE SYSTEM THROUGH SAID SEPARATOR, OR TO CAUSE RECYCLING OF THE REUSABLE BLAST MEDIA THROUGH SAID FEEDER HOPPER AND SAID BLAST MACHINE AGAINST SAID WORKPIECES. 